Fig. 2: Possible outcomes in the cyclization of enediynes.

The left box shows the conventional C1–C6 Bergman (BC) and C1–C5 Schreiner–Pascal (SP) cyclizations giving diradicals. The top right depicts the dual Au(I)-catalyzed zwitterionic version of BC, and the bottom right box shows the present work on the boron-Au(I) triggered zwitterionic BC and SP cyclizations.